I know, publication bias is not a new topic but it is still of high relevance. I found some very interesting results in a study from Annie Franco, Neil Malhotra, Gabor Simonovits published in Science (19 Sep 2014, Vol. 345, Issue 6203, pp. 1502-1505): Publication bias in the social sciences: Unlocking the file drawer. According to the authors, “only 10 out of 48 null results were published, whereas 56 out of 91 studies with strongly significant results made it into a journal.” The following figure summarizes the results:
The pattern is quite remarkable. The majority of evidence that does not support any hypothesized relationship is not even written-up in the first place. So there’s reason for doubt that special platforms or journals who publish papers with contrary findings – as it is regularly discussed for overcoming publication bias – will significantly increase the number of null results published.